Beryllium-7 and Fission Products in Surface Air

Abstract

THE existence of beryllium-7, produced naturally by cosmic-ray interactions with atmospheric constituents, was first reported in rain-water by Arnold and Al-Salih¹. During 1954 measurements on the concentration of this nuclide in surface air were made in Canada by Cruikshank et al.², using radiochemical procedures. At two of their sampling sites these authors observed a seasonal variation in the concentration of beryllium-7 which they ascribed to variations in precipitation. In 1960 we published comparative measurements on the beryllium-7 and fission product-levels in surface air which included provisional results suggestive of a related seasonal variation in the beryllium-7 and fission product concentrations³. This communication presents the results of our measurements on beryllium-7 during the period January 1960–September 1961 and on cerium-144 and cæsium-137 during the period January 1960–September 1961. The latter results form a continuation of work previously reported^3–5.